Kinetics and Mechanism of Humic Acids Degradation by Ozone in the Presence of CeO₂/AC

Abstract

This work investigated the catalytic ozonation of humic acids extracted from landfill leachate in the presence of CeO₂/AC with focus on the kinetics of humic acids degradation. It was confirmed that the degradation of humic acids mainly took place in the solution bulk. The direct and indirect reaction constants of ozone against humic acids were determined. By analyzing the contributions of direct ozone oxidation and indirect •OH radicals oxidation to humic acids removal, it was found that •OH radicals oxidation predominated at all pH, indicating that the catalytic ozonation of humic acids with CeO₂/AC involved •OH radicals mechanism.

Keywords:

• Ozone
• Activated carbon
• Catalytic ozonation
• Cerium oxide
• Humic acids
• Landfill leachate